fix error message for checking number of positional arguments

Author: zetwhite

Lib/test/test_positional_only_arg.py

@@ -145,8 +145,6 @@ def f(a, b, /):
         with self.assertRaisesRegex(TypeError, expected):
             f(a=1, b=2)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_positional_only_and_arg_invalid_calls(self):
         def f(a, b, /, c):
             pass
@@ -194,8 +192,6 @@ def f(a, b, /, c, *, d, e):
         with self.assertRaisesRegex(TypeError, r"f\(\) got an unexpected keyword argument 'f'"):
             f(1, 2, 3, d=1, e=4, f=56)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_positional_only_invalid_calls(self):
         def f(a, b, /):
             pass
@@ -292,9 +288,6 @@ def test_module_function(self):
         with self.assertRaisesRegex(TypeError, r"f\(\) missing 2 required positional arguments: 'a' and 'b'"):
             global_pos_only_f()
 
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_closures(self):
         def f(x,y):
             def g(x2,/,y2):

vm/src/builtins/function.rs

@@ -99,8 +99,8 @@ impl PyFunction {
             // Check the number of positional arguments
             if nargs > nexpected_args {
                 return Err(vm.new_type_error(format!(
-                    "Expected {} arguments (got: {})",
-                    nexpected_args, nargs
+                    "{}() takes {} positional arguments but {} were given",
+                    &self.code.obj_name, nexpected_args, nargs
                 )));
             }
         }